Re: unresoved symbol _gp_disp

From: Andi Kleen
Date: Thu Oct 04 2007 - 14:30:18 EST


"Steven J. Hill" <sjhill@xxxxxxxxxxxxxxxxxx> writes:

> > I have written a loadble module ( which gets complied
> > along with kernel) which does some floating point
> > operation.
> >
> NO FLOATING POINT in the kernel PERIOD. Either use integer
> operations, or redo your software architecture and do the
> floating point in userspace.

You can use floating point; you just have to make sure to
save the FP context explicitely and disable preemption. Details
on how to do this vary by architecture.

The problem is that FP code typically takes often a lot of CPU time
and it is quite antisocial to disable preemption for a long time
because that impacts real time latency for everybody.

Besides many uses can be relatively easily rewritten to fixed
point.

-Andi
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/